The Effects Of Pre-exercise Protein Vs. Carbohydrate Consumption On Energy Expenditure After High-volume Resistance Exercise

Abstract

During the recovery period following a bout of resistance exercise, oxygen consumption remains elevated for a variable timeframe, reflecting an acute enhancement in resting energy expenditure. What remains uncertain is whether pre-exercise nutrient consumption further promotes these acute metabolic responses to a bout of resistance exercise and if the type of nutrient influences these effects. PURPOSE: Therefore, the objective of this study was to determine, in college-age, resistance trained male subjects, the extent by which pre-exercise supplementation of whey protein or carbohydrate modulates metabolic and substrate oxidation rates following a bout of high-volume, total body resistance exercise. METHODS: In a randomized, placebo controlled, cross-over study, healthy, resistance trained male (n=10) subjects initially underwent baseline testing for resting energy expenditure and maximum strength. Subjects were familiarized with the resistance exercise protocol during the subsequent visit. Afterwards, across 3 separate subsequent visits, subjects consumed whey protein (PRO), carbohydrate (CHO), or no nutrients (CON) prior to a bout of high-volume resistance exercise. After exercise, subjects were tested for energy expenditure (EE), oxygen consumption (VO2), respiratory exchange ratio (RER), and heart rate (HR). RESULTS: PRO (+23.5%; p=0.003), CHO (+12.8%; p=0.001), and CON (+9.5%; p=0.005) increased EE from resting baseline with concomitant changes to VO2, RER, and HR. PRO (p=0.019) and CHO (p=0.003) demonstrated equivalently greater post-exercise EE than CON. Post-exercise VO2 was significantly greater in PRO vs. CON (p=0.034) while CHO did not differ from PRO or CON. CONCLUSION: Overall, nutrient consumption prior to resistance exercise may augment the post-exercise elevation in EE. Consumption of whey protein pre-exercise may enhance excess post-resistance exercise oxygen consumption (i.e EPOC) to a greater extent than carbohydrate intake.